Dermacentor Variabilis Research Articles

Complex orbitocranial penetrating injury-managed through neuroplastic surgery – a rare case report and review of literature

Introduction and importance: Orbitocranial penetrating injuries (OPI) are uncommon types of head injuries, accounting for about 0.04% of all head injuries. Foreign bodies penetrating the orbit and cranium cause fractures, leading to ophthalmic and neurological manifestations. These require a specialized treatment approach that mainly depends on the foreign body type, extent of injury, and potential complications. Management involves foreign body removal, reconstruction, and infection control. Case details: We discuss a case of a 25-year-old male who presented with a penetrating cranio-orbital injury caused by a wooden stick through the left eye. The transorbital-transcranial wooden foreign body penetrated the orbital roof and temporal bone causing displacement of the orbital contents and extended intracranially into the temporal region. The management was done by a multidisciplinary approach consisting of a team of neurosurgeons and oculoplastic surgeons by extracting the foreign body and reconstruction. Clinical discussion: No sound literature on the management of OPI by neuroplastic surgery is available. Conclusion: This article highlights the importance of neuroplastic surgery for reconstructing complex fractures involving the cranio-orbital and craniofacial regions for improving patient outcomes, and preventing potential complications. This could potentially revolutionize the management of complex craniofacial abnormalities and a new era for neuro-reconstructive care.

382. A Hot Topic: the Relationship Between Climate Variability and Vector Specific Trends in Tick-Borne Diseases in New Jersey

Abstract Background The distribution and prevalence of tick-borne diseases (TBDs) are affected by climate factors, particularly temperature and humidity, which impact tick survival and activity. Understanding how climate factors affect TBDs is crucial for public health preparedness. We investigated trends in TBDs in New Jersey (NJ) over the past two decades.Figure 1:Case counts of TBDs by vector in the (A) off-season and (B) in-season months over the years(A) Case counts of reportable TBDs in aggregate and diseases transmitted by I. scapularis significantly increased in the off-season. Diseases transmitted by A. americanum and D. variabilis did not significantly increase in the off-season. (B) Case counts of all reportable TBDs, and diseases transmitted by I. scapularis and D. variabilis did not significantly increase in the in-season. In contrast, diseases transmitted by A. americanum significantly increased in the in-season. Methods We obtained case counts of reportable TBDs from 2003 to 2022 from the NJ Department of Health (N = 85,905), and climate data from the publicly available nClimDiv dataset. We conducted linear regression analysis to assess temporal trends in total TBD cases over the 20-year period. We also used Poisson regression analysis to examine the association between TBD incidence and climate factors, specifically average temperature and total precipitation.Table 1:Case count correlation with climate parameters (average temperature and total precipitation) using univariate and multivariate Poisson regression analysis We performed a Poisson regression analysis using case count as the dependent variable, and average temperature and total precipitation as the independent variables. For the multivariate model, we utilized average temperature and total precipitation as covariates. Total case counts of reportable tick-borne diseases, and case counts of diseases transmitted by I. scapularis (Lyme disease, Babesiosis, Anaplasmosis), A. americanum (Ehrlichiosis), and D. variabilis (Spotted Fever Group Rickettsiosis) are significantly positively correlated with average temperature and total precipitation using univariate analysis. Only diseases transmitted by the American Dog Tick are positively correlated with both average temperature and total precipitation using multivariate analysis. Diseases transmitted by I. scapularis and the lone star tick are only positively correlated with average temperature using multivariate analysis. Results Total TBDs have significantly increased over the study period, particularly during the off-season (October to March; p < 0.01), while there was no significant increase during the in-season period (April to September) (Fig. 1, p > 0.05). Sub-analysis by vector revealed significant increases in diseases transmitted by Ixodes scapularis (Deer Tick; Babesiosis, Lyme disease, Anaplasmosis), particularly in the off-season (Fig. 1A; p < 0.01). In contrast, diseases transmitted by Amblyomma americanum (Lone Star Tick; Ehrlichiosis) significantly increased during the in-season period (Fig. 1B; p < 0.001). There was no significant increase in diseases transmitted by Dermacentor variabilis (American Dog Tick; Spotted Fever Group Rickettsiosis) (Fig. 1; p > 0.05). Univariate Poisson regression analysis showed a positive correlation between all TBDs and average temperature and total precipitation (Table 1). Conclusion Our findings demonstrate a rising trend in TBDs in NJ, correlated with average temperature and precipitation. Sub-analysis highlights vector-specific patterns, with I. scapularis-transmitted diseases increasing predominantly in the off-season and A. americanum-transmitted diseases during the in-season period. These findings emphasize the importance of maintaining vigilance for TBDs during traditionally low-risk months and the need for proactive strategies to mitigate the impact of climate factors on TBD transmission. Disclosures Bobby Brooke Herrera, PhD, Mir Biosciences, Inc.: co-founder Navaneeth Narayanan, PharmD, MPH, BCIDP, Astellas: Honoraria|Beckman Coulter: Honoraria|Merck: Grant/Research Support|Shionogi: Grant/Research Support Thomas Kirn, MD PhD, Selux Diagnostics: Advisor/Consultant|Selux Diagnostics: Honoraria Keith S. Kaye, MD, MPH, Allecra: Advisor/Consultant|CARB-X: Advisor/Consultant|GSK: Advisor/Consultant|Merck: Advisor/Consultant|Shionogi: Advisor/Consultant|Spero: Advisor/Consultant

386. Pathogen-Harboring Ticks are Prevalent in Suburban Green Spaces in Central North Carolina

Abstract Background North Carolina (NC) reports high numbers of ehrlichiosis and spotted fever group rickettsioses. However, the prevalence of pathogens in ticks has historically been relatively low, with a < 10% prevalence of Ehrlichia spp. and < 1% prevalence of Rickettsia rickettsii in field-collected Amblyomma americanum and Dermacentor variabilis ticks. Most entomological surveys have focused on woodlands and rural sites, while less is known about the risk of human-tick interactions in suburban green spaces such as parks.Table 1.Pathogens identified in ticks in central North Carolina from surveillance in suburban green spaces and animal shelters. Methods The objective of the study, which was supported by an IDSA GERM Award, was to describe the prevalence and distribution of pathogen-harboring ticks in a suburban area of central NC with a focus on green spaces. Tick surveillance was performed by dragging vegetation in 16 suburban green spaces, primarily city and county parks, in Orange and Chatham Counties from June - August 2022. Ticks were also collected from stray dogs presenting to two county animal shelters. Polymerase chain reaction (PCR) was used to detect pathogens in the ticks. Results A total of 107 ticks were collected and underwent PCR testing (Table 1), including 40 collected via dragging and 67 from animal shelters. A. americanum were the most frequently encountered ticks, accounting for more than two-thirds of ticks collected in green spaces and half of ticks from shelters. A total of 26% were positive for E. chaffeensis or E. ewingii, with substantially higher infection rates among ticks from shelters. A. maculatum accounted for 25% of ticks in green spaces, half of which were positive for R. parkeri. The vast majority (90%) of D. variabilis ticks were collected from shelters, but all three ticks from green spaces were positive for R. rickettsii. While of uncertain pathogenicity, R. amblyommatis was the most frequently encountered bacterium among all ticks collected. Conclusion Our findings demonstrate that pathogen-infected ticks are present in suburban green spaces. Given that exposure risk of tick-borne disease is commonly associated with rural activities such as hiking, camping, and hunting, further education and public campaigns are warranted, and vector control efforts may need to be considered. Our findings also suggest that A. maculatum may be moving further inland than previously reported. Disclosures All Authors: No reported disclosures

Spatial and temporal analyses of Dermacentor variabilis (Say) (Acari: Ixodidae) in central and eastern Canada.

Dermacentor variabilis (Say) (Acari: Ixodidae) is a vector for pathogens that can impact human and animal health. The geographic range of this species is expanding, but there are some areas with limited up-to-date information on the distribution of D. variabilis. Therefore, the objective of this study was to describe the spatial and temporal patterns of adult D. variabilis activity in central and eastern Canada. Ticks were collected from companion animals by veterinary clinic staff. Suspected locations of tick acquisition were spatially projected, and a spatial scan statistic was used to identify statistically significant clusters of frequent submissions from veterinary clinics. Submissions were categorised by calendar week to evaluate temporal trends. In total, 1198 adult D. variabilis, one nymphal D. variabilis and one Dermacentor albipictus (Packard) were collected from the provinces of Manitoba, Ontario, Quebec, New Brunswick, Nova Scotia and Prince Edward Island from April 2019 through March 2020. Peaks in adult D. variabilis submissions occurred in May and June. Most of the submissions were received from south-eastern Manitoba, eastern Ontario and central and western Nova Scotia. A statistically significant cluster of frequent submissions that included seven veterinary clinics was identified in Nova Scotia. These findings can be used to determine the locations and times at which humans and their companion animals should be considered at an increased risk of exposure to D. variabilis and the pathogens they carry.

Nation-wide surveillance of ticks (Acari: Ixodidae) on dogs and cats in Singapore.

Companion animals are major reservoirs of zoonotic parasites and pathogens. Among these, ticks and tick-borne pathogens are of particular concern. Efforts to study the zoonotic risks associated with companion animals in Singapore have been hampered by a poor understanding of the ticks of local dogs and cats. To address this knowledge gap, ticks from companion animals were collected as part of Singapore's first nation-wide tick surveillance program beginning in 2018. Under the program, a total of 362 ticks were collected from dogs and one cat. These represented three tick genera and five species: Haemaphysalis bispinosa, Haemaphysalis hystricis, Haemaphysalis papuana, Rhipicephalus linnaei, and Dermacentor auratus. The most dominant species within companion animal-tick communities in Singapore were H. bispinosa and R. linnaei. The species diversity and health risks associated with companion animal ticks in Singapore are discussed.

A scoping review of applied tick control research in North America: funding, implementation, and advancement.

Geographic ranges of ticks and tick-borne pathogens within North America are shifting due to environmental changes and human-driven activities, with species of public health concern presenting a multifaceted risk to human health. Innovative strategies and continued collaboration to control tick populations are needed to combat this growing threat. We conducted a scoping review of the literature to describe the nature of applied tick control research conducted in North America (Canada, Mexico, and the United States) to date, with the goal of describing key concepts and identifying gaps in this research area. A total of 244 articles met our inclusion criteria and were reviewed for patterns in applied tick control authorship and funding, study location, target species, and control methodology. Most studies (83.6%) were conducted exclusively in the United States and 75% focused on ticks of public health concern, principally Amblyomma americanum (Linnaeus, Acari: Ixodidae), Dermacentor variabilis (Say, Acari: Ixodidae), Ixodes scapularis Say (Acari: Ixodidae), and Rhipicephalus sanguineus (Latreille, Acari: Ixodidae). The majority of funding was provided through US federal agencies, predominantly the Centers for Disease Control and Prevention and the United States Department of Agriculture. Ixodes scapularis was the target of over 50% of identified articles, with the majority of research conducted within 3 states in the Northeast region of the U.S. Only 8.2% of included studies evaluated integrated tick management interventions. We note gaps in tick control research regarding (i) non-Ixodes medically relevant tick species, (ii) endemic range coverage, and (iii) control methodologies evaluated.

Identification and characterization of a Relish-type NF-κB, DvRelish, in Dermacentor variabilis in response to Rickettsia rickettsii infection.

Ixodid ticks serve as hosts and transmission vectors for several obligate intracellular bacteria, including members of the spotted fever group (SFG) of Rickettsia. Although ticks generate an immune response to bacterial insults, many of the signaling molecules associated with the response and how they may contribute to vector competence for Rickettsia are undefined. In this study, we isolated a full-length dvrelish transcript from Dermacentor variabilis, which encoded a Relish-type NF-κB. The presence of a canonical Rel homology domain (RHD) consistent with NF-κB proteins suggested a role in tick immune response for DvRelish. The expression of DvRelish was confirmed in tick tissues and fluorescent microscopy of tick hemocytes indicated increased expression following infection with Rickettsia as compared to a non-tick-borne bacterial pathogen. To further determine the effect of dvRelish gene knockdown on rickettsial infection, we used RNA interference-mediated gene knockdown in D. variabilis and demonstrated that transcription of dvRelish was decreased after 24h post-injection of siRNA. We then assessed the response of D. variabilis when exposed to Rickettsia rickettsii and determined that transcription of dvRelish was inversely associated with rickettsial loads at 48h post-exposure. Further studies are required to broaden the understanding of differential immune responses in ticks to SFG Rickettsia infection and elucidate the role played by the arthropod immune system in vector competence.

A Retrospective Epidemiological Analysis of Microscopically Detected Babesiosis in Dogs of Southern Poland (2018–2022)

Babesia canis is the parasite responsible for a life-threatening disease for dogs in Central Europe, of which the main vector is the ornate dog tick—Dermacentor reticulatus. The objective of the presented study was to assess the prevalence of Babesia infection in dogs with clinical suspicion of babesiosis, which tested positive for B. canis from locations where there is no or very limited information about dog exposure to this pathogen. In order to confirm the presence of this protozoan, blood samples were collected from dogs treated in veterinary clinics with suspicion of canine babesiosis. The samples were sent for microscopic analysis to Vetlab, a commercial veterinary diagnostic laboratory, to confirm the diagnosis. Overall, 3032 dog blood samples from Southern Poland were examined between 1 August 2018 and 31 December 2022 at the Vetlab laboratory. A total of 282 (9.3%) samples were found to be Babesia-positive using Wright–Giemsa stain peripheral blood smears, with an increase in two periods per year—April and October. Among the five voivodships, from which the laboratory analyzed blood samples, the highest number of Babesia-positive samples came from Częstochowa (Silesia) and its surroundings. Moreover, Babesia protozoans occurred more frequently in blood smears of pure-breed rather than mixed-breed dogs. The obtained results showed that infections with large Babesia in dogs from Southern Poland (with a special indication for the Śląskie Voivodship) should be taken into consideration during the differential diagnosis of tick-borne diseases at veterinary clinics. The presented study increases the vigilance and awareness of veterinarians and dog owners in this region, where babesiosis was very rarely diagnosed until date.

Lack of host‐associated differentiation in Ixodes scapularis using population genetics

AbstractThe blacklegged tick, Ixodes scapularis (Say) (Acari: Ixodidae), is a vector of pathogens that cause diseases including anaplasmosis, babesiosis, and Lyme disease. It is a generalist vector feeding on a wide variety of vertebrate hosts. The transmission cycles of these pathogens are affected by the tick's host selection because host species differ in their ability to clear, maintain, or amplify these pathogens. Several generalist parasites exhibit host‐associated differentiation (HAD), a process that results in genetically distinct populations associated with different host species. Knowing whether I. scapularis exhibits HAD is important to better understand the ecology of these diseases. To test for HAD in I. scapularis, whole‐genome resequencing was performed on ticks collected directly from six hosts in the southern United States (i.e., cotton mice [Cricetidae: Peromyscus gossypinus Le Conte], opossum [Didelphidae: Didelphis virginiana Kerr], raccoon [Procyonidae: Procyon lotor L.], gray fox [Canidae: Urocyon cinereoargenteus Schreber], wild boar or feral hog [Suidae: Sus scrofa L.], and white‐tailed deer [Cervidae: Odocoileus virginianus Zimmermann]). For the hosts tested, HAD was not found. However, it could not be ruled out if HAD is occurring for ticks associated with lizards in this study. The results of this study contrast with findings from another host generalist, Dermacentor variabilis (Say), that does exhibit HAD. Our results suggest that these two tick species differ in their propensity for HAD. One explanation could be that I. scapularis can mate off‐host, maintaining panmixia, whereas D. variabilis mate only on the host. The lack of HAD in I. scapularis should be confirmed by sampling ticks from lizard and rodent hosts. These results will inform control efforts and the use of area‐wide tick control strategies.

Use of diatomaceous earth to control nymphal American dog ticks,Dermacentor variabilis Say (Acari: Ixodidae): laboratory to simulated field experiments.

Diatomaceous earth (DE) recently was shown to rapidly kill ticks. Proof of concept for use of DE to kill the American dog tick, Dermacentor variabilis, the most widely distributed native three-host tick in North America, has not been investigated. Unfed D. variabilis nymphs dipped into DE and incubated at 30 °C and 50 versus 70% relative humidity (RH) had an estimated median survival time of 5h and 4h, respectively, with mortality starting within 1h. There was no difference in survival time at the 50 and 70% RH. In a two-choice assay at 30 °C and 50% RH, ticks walked freely onto DE treated surfaces; the estimated median survival time was 3h, indicating that DE is not a repellent. There was no difference in locomotor activity between DE-treated nymphs and untreated controls. In simulated-field experiments, pine straw infested with nymphs and then treated with DE at 5.00, 2.50, 1.25, 0.63 and 0.31g DE/m2 resulted in 100% mortality and 81.40% (± 4.13%) mortality at 0.15g DE/m2 after 24h. Scanning electron microscopy of the dead ticks in the 0.15g DE/m2 treatments showed most of the cuticle surface was devoid of DE except for the hypostome. The rapid time to first death by dipping, the no effect of RH on survival time, the small amounts of mineral on the tick body and no visible scarring on the tick cuticle questions the generally accepted mode of action for DE, that is, cuticle damage and dehydration.

Bacterial Microbiota of the Brown Dog Tick (Rhipicephalus sanguineus), a Broad Starting Point to Establish Potential Pathogens in Northern Mexico

Bacterial Microbiota of the Brown Dog Tick (Rhipicephalus sanguineus), a Broad Starting Point to Establish Potential Pathogens in Northern Mexico

Severe and Fatal Rocky Mountain Spotted Fever After Exposure in Tecate, Mexico - California, July 2023-January 2024.

Rocky Mountain spotted fever (RMSF) is a tickborne disease endemic in areas of the Americas. Persistent high incidence of the disease exists in northern Mexico, perpetuated by local populations of brown dog ticks (Rhipicephalus sanguineus sensu lato) and free-roaming dogs. Six cases of RMSF caused by Rickettsia rickettsii, including three deaths, were reported to the California Department of Public Health during July 2023-January 2024. All six patients were eventually determined to have had exposure to R. rickettsii in Tecate, Mexico, a municipality on the U.S. border that had not been previously described as a high-risk RMSF area. Identification and reporting of the cases were complicated by challenges in diagnosis. The serious nature of the disease and delays in initiating appropriate treatment can result in life-threatening consequences. Epidemiologic collaborations among local, state, federal, and international public health agencies were essential to identifying Tecate as the location of exposure. Further collaborations will be important for directing future prevention measures. Increased health care provider awareness of RMSF is critical on both sides of the border to facilitate earlier diagnosis and initiation of appropriate treatment.

Transmission risk of vector-borne bacterial diseases (Anaplasma spp. and Ehrlichia canis) in Spain and Portugal

BackgroundEhrlichiosis and anaplasmosis are vector-borne bacterial diseases produced by intracellular rickettsial species of the genus Ehrlichia and Anaplasma. Ehrlichia canis and Anaplasma spp. (A. platys and A. phagocytophilum) have reported cases of zoonotic transmision and are the main bacterial agents of canine ehrlichiosis and anaplasmosis. They normally present an asymptomatic or mild course in domestic and wild animals with some lethal cases reported. The main vector of these diseases in Europe are the castor bean tick (Ixodes ricinus) and the brown dog tick (Rhipicephalus sanguineus), although only in the latter, the main host is the domestic dogs. The aim of this work is to apply an integrative approach to convert ecological niche models (ENMs) into potential transmission risk models and understand the relative contribution of the two potential vectors (R. sanguineus and I. ricinus) to spread both diseases in the Iberian Peninsula and Balearic Islands.ResultsTwo ENMs meeting all criteria were successfully generated for R. sanguineus and I. ricinus with human footprint being the most relevant explanatory variable. The novelty of the study lies in the combination of independent ENMs for both species to estimate the disease transmission risk of specific bacteria (E. canis, A. platys and A. phagocytophilum). Only the transmission risk maps that had higher contribution of R. sanguineus than I. ricinus showed relevant and positive significant correlations between risk and seroprevalence in either of the two species of bacteria (R ≥ 0.4; p < 0.05). Regarding Anaplasma spp., the map having 10% contribution of I. ricinus (10I) and 90% of R. sanguineus (90R) inferred 47.4% of infected dogs in very high-risk areas. In the case of E. canis, the model showing a proportion of 25I-75R showed better validation power (53.4% of infected dogs in very high-risk areas).ConclusionThe validation approach used in this study produced a good approximation to understand the relative contribution of the two tick species in bacterial disease transmission in dogs in the Iberian Peninsula and Balearic Islands. Rhipicephalus sanguineus appears as the main transmitter of both diseases in the study area (90% and 75% for anaplasmosis and ehrlichiosis respectively), in accordance with its higher abundance and host preference. This estimate may help veterinary staff, clinicians and owners to optimize the control of these diseases in certain vulnerable areas, and thus reduce the risk of infection in risk areas.

Preclinical safety assessment in rats after dermal exposure to acetylcarvacrol, a potential acaricide against the brown dog tick

Carvacrol, a phenolic monoterpene found in essential oils of plants of the Lamiaceae family, emerges as an alternative acaricide of plant origin. Its acetylation was proposed to obtain a derivative compound with a better pharmacological profile and lower toxicity to non-target organisms. The present study aimed to assess the preclinical safety of acetylcarvacrol after dermal application in Wistar rats, through the examination of hematological and biochemical parameters, as well as histopathological analysis of the skin, liver and kidney. For this, twenty rats were distributed into four groups with five animals each. Three groups received treatment with different concentrations of the substance (26, 52, and 104 µL/mL) based on the lethal concentration for Rhipicephalus sanguineus ticks, and one group (Control) received only the vehicle. Acetylcarvacrol was applied daily to a trichotomized skin area for 21 days. No changes in hematological parameters were observed. Regarding biochemical analysis, a slight increase in urea and alanine transaminase levels was noted. No significant changes were observed in the kidney and liver, although the rats had developed cumulative irritant contact dermatitis at the application site, as corroborated by the histopathological analysis of the skin. In general, the results showed that the dermal application of acetylcarvacrol in the experimental conditions described here is safe. However, it can cause signs of mild systemic toxicity and skin irritation at high concentrations, suggesting that this product should be used in lower therapeutic doses and that the development of less aggressive formulations, including the combination with other acaricides, is desirable.

Effects of permethrin-treated uniforms on tick submissions to a military passive tick surveillance program.

Permethrin-treated clothing is often recommended as a first line of defense against tick-borne diseases. In 2012, the permethrin factory-treated Army Combat Uniform was first made available to active duty Soldiers, Army National Guard, Army Reserve Enlisted Soldiers, and the Senior/Junior Reserve Officers Training Corps. Subsequently, Air Force and Marine Corps personnel were also offered permethrin factory-treated uniforms. Here, we use the passive surveillance data collected through the Military Tick Identification/Infection Confirmation Kit (MilTICK) program to determine the effectiveness of permethrin-treated uniforms at protecting Department of Defense personnel from exposure to tick-borne pathogens in the United States. We analyzed whether submissions by self-reported users of the permethrin-treated uniforms had smaller proportions of engorged ticks, certain cohorts of MilTICK users were better protected than others, and specific tick species were better repelled than others. We found that permethrin use resulted in significantly lower proportions of engorged ticks submitted across MilTICK users. Army and Army National Guard personnel reported more permethrin-treated uniform use than other services. For submissions from active duty personnel serving in uniform, the proportion of tick engorgement in the presence of permethrin increased over time, possibly indicating that permethrin-treated uniforms suffer from reduced performance over the life of the garment. We also found that while permethrin reduced all tick species' ability to feed until engorgement or repletion, blacklegged tick adult females were better able to resist permethrin's lethal effects than lone star tick and American dog tick adult females. Permethrin-treated clothing plays an important role in keeping military personnel safe from tick-borne diseases.

Rhipicephalus simus ticks: new hosts for phleboviruses.

Ticks are widespread arthropods that transmit microorganisms of veterinary and medical significance to vertebrates, including humans. Rhipicephalus simus, an ixodid tick frequently infesting and feeding on humans, may play a crucial role in transmitting infectious agents across species. Despite the known association of many Rhipicephalus ticks with phleboviruses, information on R. simus is lacking. During a study in a riverine area in Lusaka Zambia, ten R. simus ticks were incidentally collected from the grass and bushes and subjected to metagenomic next generation sequencing (mNGS) in 2 pools of 5. Analysis detected a diverse microbial profile, including bacteria 82% (32/39), fungi 15.4% (6/39), and viruses 2.6% (1/39). Notably, viral sequence LSK-ZM-102022 exhibited similarity to tick phleboviruses, sharing 74.92% nucleotide identity in the RdRp gene and 72% in the NP gene with tick-borne phlebovirus (TBPV) from Greece and Romania, respectively. Its RNA-dependent RNA polymerase (RdRp) encoding region carried conserved RdRp and endonuclease domains characteristic of phenuiviridae viruses. Phylogenetic analysis positioned LSK-ZM-102022 in a distinct but lone lineage within tick phleboviruses basal to known species like brown dog tick phlebovirus and phlebovirus Antigone. Pair-wise genetic distance analysis revealed similar findings. This study emphasizes the urgency of further research on the ecology, transmission dynamics, and pathogenic potential of LSK-ZM-102022 and related TBPVs, crucial for local and global preparedness against emerging tick-borne diseases.

Impaired humidity sensing reduces tick survival by preventing water homeostasis.

Off-host periods are critical for ticks, representing a period when environmental stress, particularly dehydration, can impact tick survival. To prevent dehydration, ticks must be able to detect and move into high humidity areas to allow for water vapor uptake. Ionotropic receptor 93a (Ir93a), which is highly expressed in the front forelegs (location of Haller , s organ), increases expression following dehydration, suggesting a role in humidity detection. Although the Haller , s organ is suggested as the site of humidity detection in ticks, humidity detection has not been extensively examined. Here, we assessed the ability of American dog ticks, Dermacentor variabilis , to sense humidity and how altered humidity detection impacts tick survival by manipulating the Haller , s organ. Permanent (cutting or heat ablation) or temporary blocking (silicone covering) of the Haller , s organ impairs the ability of the American dog tick, Dermacentor variabilis, to rest in areas necessary to maintain hydration. Impaired detection of humidity did not impact tick survival when individuals were held under stable optimal conditions. Still, variable conditions (low and high humidity gradient) reduced survival through dehydration stress and decreased energy reserves, as chronic water vapor uptake is energetically expensive. Field validation of these studies in D. variabilis confirmed that humidity detection is critical to tick survival. Lastly, modeling indicates impaired humidity detection will reduce questing tick populations, specifically in the adult stages. These studies confirm that the Haller , s organ is critical for humidity sensing in ticks. Without this ability, tick survival will be impaired by potential dehydration or more rapid depletion of energy reserves.

Comparative toxicity of three variant oils and their nanoemulsions on the brown dog tick Rhipicephalus sanguineus

Tick control mainly depends on using chemical acaricides that have led to the emergence of resistant tick populations along with environmental hazards. Natural alternatives including essential oils are now widely used to avoid the undesirable effects of chemicals on human, animals and environment. In this study, three commercial oils (myrrh, patchouli, and cypress) and their nanoemulsions (NEs) were tested against Rhipicephalus sanguineus sensu lato unfed adults. Transmission electron microscopy (TEM) and dynamic light scattering (DLS) were used to characterize the nanoemulsions. Four concentrations with three replicates were used in the bioassay of oils and NEs against ticks using an adult immersion test. Furthermore, a toxicity study of the three oils and their NEs using normal fibroblast cells (BJ-1) was performed. TEM revealed particle size ranges from 29 to 211 nm with spherical droplets. The droplet size and polydispersity index were (29.30 nm & 0.367), (211.6 nm & 0.221) and (164.2 nm & 0.237) for myrrh NE, patchouli NE, and cypress NE, respectively. Myrrh and patchouli oils recorded high acaricidal activity followed by cypress oil with LC50 value 5 days after treatment of 9.01, 12.40, and 15.21%, respectively. The acaricidal efficacy of oil was potentiated in the NEs form which was proved by the reduction in LC50 values that were recorded 7 days after treatment 4.17, 8.57, and 5.04%, for myrrh, patchouli, and cypress NE, respectively. As an alternative for lab animals, we applied the cytotoxicity of myrrh, patchouli, and cypress on normal fibroblast cells. The oils showed low cytotoxic activity of 10.6, 21.5, and 23.6% for Myrrh, Patchouli, and Cypress, respectively. The nanoemulsion was revealed to be safe for normal cells up to a concentration of 0.62% (cytotoxicity%= 24.4, 34.4, and 16.3%, respectively), and the moderate cytotoxic effect appeared at around a concentration of 1.25% (cytotoxicity%= 42.2%, 57.0%, and 36.8% respectively). In conclusion, the three oils and their NEs have good acaricidal activity against Rhipicephalus sanguineus unfed adults. Further toxicity studies on mammals are needed to ensure the safe use of these formulations for the control of ticks on infested animals.

A novel chemokine binding protein 1-like gene is vital for the blood pool development and engorgement of the hard tick Haemaphysalis longicornis

Tick saliva modulates host responses during a blood feeding process. We identified a novel chemokine binding protein 1-like (HLCBP1-like) gene from the salivary glands of the Asian longhorned tick, Haemaphysalis longicornis. The HLCBP1-like protein, lacking a well-defined conserved domain, showed structural similarity to evasin, a chemokine binding protein from the brown dog tick, Rhipicephalus sanguineus. A preliminary knockdown study of HLCBP1-like revealed that ticks with reduced expression of this gene, halted feeding in the early feeding phase, and did not fully-engorge, unlike the control dsRNA (malE) injected ticks. Also, knockdown ticks induced cellular immune responses in the host skin, similar to control dsmalE-injected ticks, but did not show hemorrhage. These findings suggest that HLCBP1-like may play a modulatory role in the slow feeding phase.

Detection of Anaplasma bovis-like agent in the Southcentral United States

Anaplasma bovis is primarily an infectious agent of ruminants, and has most commonly been reported in Asia, the Middle East, and Africa. Although the primary cause of human anaplasmosis is Anaplasma phagocytophilum, humans may rarely be infected by other Anaplasma spp. Human disease attributed to A. bovis has been occasionally reported, including an A. bovis-like agent in the United States. DNA of an A. bovis-like agent has been amplified from humans and the tick Dermacentor variabilis in the central region of the U.S., but larger prevalence studies among potential vectors or reservoir hosts in the U.S. have not been reported. The aim of this study was to evaluate the prevalence of A. bovis-like agent among D. variabilis and cattle in the Southcentral U.S. Previously extracted DNA from adult D. variabilis collected from Oklahoma (n = 38) and Kansas (n = 93), and blood of cattle from Oklahoma (n = 140) were tested by conventional PCR. Overall prevalence of A. bovis-like DNA within ticks was determined to be 3.1% (4/131), and all positive ticks originated from Oklahoma. Overall prevalence in bovine blood was determined to be 0% (0/140). These findings confirm the presence of an A. bovis-like agent, a potentially zoonotic pathogen, among ticks in the Southcentral U.S.; this agent is likely underrecognized and has been detected in parts of the U.S. that lie outside of the established geographic range for A. phagocytophilum. Further investigation and surveillance are necessary to elucidate possible reservoirs of A. bovis in the U.S., further evaluate the burden of human infection, and fully characterize genetic differences between the A. bovis-like agent detected in the U.S. and A. bovis in other regions of the world.